In a known battery pack for an electric vehicle, a plurality of rectangular battery modules are placed on a base plate supported by the vehicle in a grid pattern, and each column of battery modules are jointly secured to the base plate by a strap extending in the fore and aft direction of the vehicle. See JPH07-52660A and JPH07-81432A, for instance.
In such a conventional battery pack, each securing strap is attached to the parts of the base plate adjacent to the fore and aft end parts of the battery pack so that the battery pack is allowed to extend over the entire width of the vehicle. Thereby, a relatively large battery pack can be accommodated in the limited space of the vehicle.
However, it has been noted that the securing straps extending in the fore and aft direction provide a limited retaining force against the lateral tilting movement of the battery modules. In particular, it is desired to retain the battery pack in a secure manner even when subjected to a lateral impact that could be caused by a side crash.